This invention relates to animal cages, more specifically, to cages used to house egg-laying hens after they have attained maturity.
Egg-producing hens are typically housed in a series of metal cages connected in a side-by-side arrangement. The rectangular cages are generally made of metal wire only--all four sides and the top and bottom. The wire construction of the cages is typically a one-inch by two-inch grid configuration, and the cages typically measure twelve by eighteen inches, with four hens to a cage. The bottom of the cage slopes downwardly toward the front of the cage to allow the eggs produced by the hens to roll to the collecting apron at the front, where the eggs will be collected by either manual pick-up or a conveyor. After hens in a modern egg-producing operation have attained sufficient maturity to produce eggs, they spend the remainder of their productive lives in these types of cages. Excrement from the hens in the cage is frequently cleaned out of the cages by the action of the hens moving therein, the one by two-inch grid of the cage floor being large enough to allow manure droppings to fall through. There may be an additional cleaning by "henhouse" caretakers. After several years of occupation and use by hens, the cages tend to develop some rust spots on the cage floors, due to continuous motion of the hens wearing off the original wire coating and thereby exposing the steel wire. As a result of the excrement of the hens and the cleaning which are carried out periodically, and of ordinary oxidation due to the environment, the wire cage bottoms begin to rust. An undesirable result--aside from the cage floor eventually becoming structurally weakened--is that the rust marks on the cages tend to leave rust marks on the eggs which are laid on the wire bottoms and which roll down the cage bottom into the cage apron. These rust marks cannot feasibly be removed from the eggs, and therefore render the eggs significantly less desirable to the consumer.
Typically, rust stained eggs are sold at greatly reduced prices to egg cracking plants for processing into powdered eggs or other egg derivative products. Further, when the rust problem becomes very extreme, the hen cages must be replaced or repaired. The procedure for repairing such cages requires that the connected cages in the building be removed for replacement of the worn bottoms, a costly and time consuming venture, to say nothing of the difficulty and inconvenience of having to move the hens from the cages during the repair operation.
Attempted solutions of the corrosion and rust problem have included the use of nylon mesh material for hen cage floors, and also various resilient mats, as, for example, in Marr U.S. Pat. No. 3,726,255 (spongy neoprene matt), Erfeling U.S. Pat. No. 3,760,769 (soft rubber or polyvinylchloride plastic floor grate), Barlocci U.S. Pat. No. 3,381,664 (snap-apart plastic cage), and Keen U.S. Pat. No. 3,641,983 (resilient mesh anti-blister mat). None of these attempted solutions has proven to be economically acceptable in that they are not feasible for widespread use in thousands of cages in a modern egg producing operation. For example, the Erfeling floor grate assembly and the Barlocci plastic cage both require relatively expensive materials and fabricating techniques. The Keen anti-blister cage mat, designed for use in connection with chickens raised for their meat production rather than egg production, is adapted for loose placement on a mesh cage floor, and does not allow for securing or locking the cage mat to the cage bottom. Similarly, the Marr cage mat is fabricated from a soft, resilient material, and cannot easily, if at all, be secured to the bottom of the cage. If the cage cover or mat is not secured to the cage bottom, then the wire bottom may continually become re-exposed to the hens and eggs laid by the hens, if the hens' motion tends to move the cage mat.
It is apparent that a cage floor covering is needed which can be used to inexpensively refurbish worn and rusted cage bottoms, substantially eliminate the rust problems, and provide an additional desirable characteristic of being more comfortable to the hens in the cages. The subject invention provides such an improvement in the art.